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What is Chalaza?

Mary McMahon
Mary McMahon
Mary McMahon
Mary McMahon

A chalaza (plural chalazae) is a structure inside an egg that helps to keep the yolk in place. It attaches to either end of the yolk and anchors it to the inside of the eggshell, essentially suspending the yolk. These structures prevent the yolk from being damaged, promoting the healthy development of the embryonic bird. They are also present in some plants, performing a similar function in plant ovules.

Many people who cook with eggs have found a chalaza or two in their work, and they look like a little stringy white rope inside the egg. Sometimes, both are visible, especially in fresh eggs, and in other cases, only one can be found. The structure is perfectly safe to eat, although some people remove it because they are concerned about its impact on the texture of a dish. A fine custard, for example, might be disrupted by its stringiness.

The chalaze helps to keep the yolk of an egg in place.
The chalaze helps to keep the yolk of an egg in place.

Originally, the chalaza starts out like a thin string. Over time, the structure usually becomes twisted, as the yolk moves around inside the egg. The chalazae develop a spiral pattern, exactly like a string that has been repeatedly twisted, and the twists stay in place because of the weight of the yolk prevents them from unwinding.

In addition to this structure, and the yolk and the white with their respective membranes, eggs also include a thin membrane between the white and the shell, and an air cell between the membrane and the egg, which develops as the contents of the egg shrink. Over time, the air cell becomes larger, and a big one can be a sign that an egg is old.

The fresher an egg is, the more noticeable the chalazae are. Some cooks regard a prominent set as a sign of very high quality, although they only really reflect freshness. For quality, the color of the yolk has to be considered, and the darker the yolk, the more nutritious the egg. Pale yolks indicate poor nutrition, and these eggs tend to not perform as well in cooking and baking. They may have trouble, for example, acting as binders in a dish, and they also provide fewer nutrients to the consumer.

Chalazae are sometimes assumed to be the start of an embryo, but they are not. Fertile eggs can actually be identified by a small dark spot and signs of red veining on the yolk.

Frequently Asked Questions

What is a chalaza and what function does it serve?

The chalaza is a pair of spiral bands anchored to the ends of an egg's yolk, ensuring it remains suspended in the center of the egg white (albumen). This central positioning is crucial for the developing embryo, providing it with consistent warmth and cushioning from external movements or shocks.

Can you see the chalaza in all types of eggs, and is it safe to eat?

Yes, the chalaza is visible in most bird eggs, including those commonly consumed by humans, such as chicken eggs. It appears as a string-like structure and is perfectly safe to eat. Its prominence can vary but is often more noticeable in fresher eggs.

Does the presence of a chalaza indicate egg freshness?

Indeed, the visibility of the chalaza can be an indicator of egg freshness. In fresh eggs, the chalaza is more prominent and tightly coiled. As the egg ages, the chalaza becomes less visible and the yolk may move more freely within the egg white, suggesting a decline in freshness.

Is the chalaza important for the development of the embryo?

For fertilized eggs, the chalaza plays a vital role in embryonic development. It helps keep the yolk, which contains the genetic material and nutrients for the growing embryo, stable and properly oriented within the protective environment of the egg white and shell.

How does the chalaza affect the cooking or baking process?

The chalaza does not significantly affect the cooking or baking process. While some cooks prefer to remove it for aesthetic reasons, especially in dishes like custards where a smooth texture is desired, it is generally not noticeable once the egg is cooked or incorporated into recipes.

Are there any nutritional benefits associated with the chalaza?

The chalaza itself does not offer any distinct nutritional benefits separate from the rest of the egg. It is composed of the same proteins found in egg whites and is consumed along with the egg without any additional health considerations.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a AllThingsNature researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a AllThingsNature researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...

Discussion Comments

anon948834

I found a round marble sized white lump next to the yolk of one of my duck eggs. It scared me. Any idea what it is? Could it be a giant chalaza?

burcinc

The chalaza I have seen doesn't look like a string. It always looks like a little white lump next to the egg yolk. I have never worried about what it is and just mix it all together when I'm making my omelet.

I have a friend who actually has a little gadget for removing chalazae. I think it's kind of funny but she says it looks unappetizing with it. I guess it's fine if it bothers you when you are cooking but I know it's completely safe.

SteamLouis

Good to know! I have thrown out several eggs before because I thought that the chalaza was a fungus or something. Now I won't worry about what it is and won't waste any eggs. Thanks!

ysmina

What makes the chalaza less visible with time? I have eaten farm eggs and store bought eggs but have never seen a chalaza. I do always see the membrane between the shell and the egg though. It's really apparent after the egg has been boiled.

Oh and another cool fact which I learned from my mom is that after you boil the egg, you will see greenish areas in the yolk. Those green parts are actually the iron content of the yolk.

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    • The chalaze helps to keep the yolk of an egg in place.
      By: Ingae
      The chalaze helps to keep the yolk of an egg in place.